The conventional framework for understanding reactivity and selectivity in organic reactions fails for reactions influenced by dynamic effects. It is proposed to investigate the role of dynamic effects in some of the most common and important reactions in chemistry. Our work with dynamic effects in sigmatropic rearrangements has recently led to a successful strategy for the control of selectivity in these reactions. We plan to extend this strategy to cover a broad array of reactions and develop catalytically enantioselective sigmatropic rearrangements. Another new emphasis in our research is the role of solvent dynamics in reactions. Following up on recent results with the Wittig reaction and arene nitration, we will develop an understanding of how solvent dynamics affects experimental observations in a series of polar reactions. Alkoxy radical cleavage reactions give us a rare opportunity to vary on a near continuum barriers, structure, and excess energy to examine the rules that govern the onset and degree of dynamic effects. Alkoxy radicals are important to broad areas of chemistry, and we aim to understand how dynamics affects their reactions. Following on our prior work with hydroboration and ozonolysis, we aim to examine the reactions induced by the generation of extremely ?hot? intermediates or products in ordinary reactions. The health-relatedness of this work derives from its impact on both strategies to control reaction selectivity and the understanding of reactions important in the synthesis of medicinally important substances and reactions important in biological pathways.